Systems and methods optimizing backhaul transport

ABSTRACT

Systems and methods optimizing backhaul transport with respect to communication systems through the use of a heterogeneous backhaul link configuration and corresponding implementation of backhaul link path selection control to provide traffic offloading for traffic congestion mitigation are disclosed. Heterogeneous backhaul link configurations may include one or more backhaul links implementing a plurality of data paths providing different capabilities, such as may comprise a high reliability path and an unpredictable reliability path. Backhaul link path selection control of embodiments implements logic for determining when data is to be carried via one or more of the backhaul link paths.

TECHNICAL FIELD

The invention relates generally to communication systems and, moreparticularly, to optimizing backhaul transport with respect tocommunication systems.

BACKGROUND OF THE INVENTION

The use of various devices which facilitate communications and/or whichthemselves utilize communications has become nearly ubiquitous. Forexample, personal computers (PCs), personal digital assistants (PDAs),electronic book readers, cellular telephones, personal media players,etc. widely in use today often utilize network connectivity, such as toprovide user communication links, upload/download of content, operationsand control communication, etc. Accordingly, various networkinfrastructure has been deployed to provide networks, such as local areanetworks (LANs), metropolitan area networks (MANs), wide area networks(WANs), and the Internet, facilitating the foregoing communications.

The foregoing network infrastructure often implement various forms ofcommunication links for facilitating the desired communications. Forexample, various edge devices (e.g., access points (APs), base stations(BSs), node Bs, etc.) may provide wireless links for connecting terminaldevices (e.g., PCs, PDAs, electronic book readers, cellular telephones,personal media players, etc.) to a network to facilitate communications.Backhaul links may, for example, be provided between such edge devicesand other network nodes of the network infrastructure (e.g., routers,switches, concentrators, gateways, etc.) to provide broadbandcommunication to the core or backbone network. Such backhaul links may,for example, be used to provide trunking with respect to the data flowsof all active terminal devices in communication with a correspondingaccess point providing a backhaul link to network resources.

The foregoing backhaul links may comprise wireless (e.g., radiofrequency (RF)) or wireline (e.g., copper cable or fiber optic) links.Irrespective of the particular communication media utilized with respectto the backhaul links, these links are typically provided as highreliability links in order to facilitate predictable communicationsmeeting the requisite quality of service (QoS) obligations for theterminal devices or other communications endpoints. Such highreliability links provide a limited network resource (e.g., bandwidthlimited, channel limited, capacity limited, etc.). For example, wirelessbackhaul links are often provided using licensed spectrum, such that achannel or channels within the licensed spectrum is reserved forproviding one or more backhaul links. The use of such licensed spectrumis advantageous because interferers (i.e., systems unassociated with thenetwork or backhaul link operating within the licensed spectrum) may besubstantially eliminated due to the restrictions of the licensing.However, the licensed spectrum comprises a specific block of spectrum,the size of which presents limitations with respect to the channels,bandwidth, and capacity that may be accommodated.

It is not uncommon for the demand for communications by various networknodes (e.g., the aforementioned terminal devices) to, at leasttemporarily, exceed the capabilities of a backhaul link used inproviding a network link. Accordingly, various schemes for avoidingnetwork congestion have been tried. For example, network congestionavoidance according to such schemes may be implemented by dropping datapackets as network traffic reaches or nears network resource congestion.As can be readily appreciated, it is generally not desirable to dropdata packets as such behavior may result in failed communication links(e.g., where a terminal device detects a sufficient level of droppedpackets to conclude the link in unreliable or otherwise unacceptable),poor quality of service (e.g., jitter, missing data, etc.), inefficientoperation (e.g., repeated data retransmission attempts, repeatedattempts to reestablish the link, etc.), and the like.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to systems and methods optimizingbackhaul transport with respect to communication systems through the useof a heterogeneous backhaul link configuration and correspondingimplementation of backhaul link path selection control to providetraffic offloading for traffic congestion mitigation. A heterogeneousbackhaul link configuration according to an embodiment herein includesone or more backhaul links implementing a plurality of data paths,wherein data paths of the plurality of data paths provide differentcapabilities (e.g., differing reliability, robustness, etc.). Forexample, a backhaul link of embodiments herein may comprise a highreliability path (e.g., using licensed RF spectrum) and an unpredictablereliability path (e.g., using unlicensed RF spectrum). Backhaul linkpath selection control of embodiments implements logic for determiningwhen data is to be carried via one or more of the backhaul link paths.Continuing with the foregoing example, the backhaul link path selectioncontrol may determine during periods of backhaul congestion (e.g., whenthe high reliability path is at or near capacity) that some portion ofthe data is to be carried by a high reliability path, another portion ofthe data is to be carried by an unpredictable reliability path, and/orstill another portion of the data is to be dropped.

Backhaul transport configurations of embodiments of the inventionprovide operation for optimizing point-to-point backhaul link transport(e.g., a non-line of sight point-to-point backhaul link) throughimplementing backhaul link path selection control to provide trafficoffloading for traffic congestion mitigation. For example, in apoint-to-point backhaul transport configuration the backhaul link pathselection control may provide for all backhaul data to be carried by ahigh reliability path of the point-to-point backhaul link until thecapacity of that path is neared or reached. Thereafter, the backhaullink path selection control may determine data to be carried by anunpredictable reliability path of the point-to-point backhaul linkduring the period in which the high reliability path is experiencingcongestion. Determinations by logic of the backhaul link path selectioncontrol regarding the carrying of data by the unpredictable reliabilitypath may be based upon QoS requirements for the data flows, fairnessmetrics for the data flows, aspects of the data flows (e.g., applicationtype, Internet protocol (IP) address, port, etc.), and/or the like.

Backhaul transport configurations according to embodiments hereinprovide operation for optimizing point-to-multipoint backhaul linktransport (e.g., non-line of sight point-to-multipoint backhaul links)through implementing backhaul link path selection control to providetraffic offloading for traffic congestion mitigation, wherein the linksof the point-to-multipoint backhaul links share resources (e.g., utilizea same channel frequency). For example, in a point-to-multipointbackhaul transport configuration the backhaul link path selectioncontrol may provide for all backhaul data to be carried by highreliability paths of the point-to-multipoint backhaul links until thecapacity of a shared backhaul link resource of the high reliabilitypaths is neared or reached. Thereafter, the backhaul link path selectioncontrol may determine data, if any, to be carried by an unpredictablereliability path of one or more backhaul link of the point-to-multipointbackhaul links and/or data, if any, to be dropped during the period inwhich the shared backhaul link resource is congested. Determinations bylogic of the backhaul link path selection control regarding the carryingof data by the unpredictable reliability path and data to be dropped maybe based upon the source of the congestion, the quality of theunpredictable reliability path, QoS requirements for the data flows,fairness metrics for the data flows, aspects of the data flows, and/orthe like.

In operation according to embodiments herein, the decisions regardingthe handling of backhaul data made by the backhaul link path selectioncontrol are preferably made with respect to data flows rather than forindividual data packets. Accordingly, the number of data flows, andcorrespondingly the number of network nodes, affected by the use of anunpredictable reliability path for backhaul transport of data and/or thedropping of data according to embodiments may be minimized.

From the foregoing it can be appreciated that a carrier or other entityproviding backhaul communication infrastructure may provide a pluralityof transport paths for a backhaul link, wherein the backhaul link pathshave unequal capabilities. One such backhaul link path may provide highreliability but limited capacity (e.g., the high reliability backhaullink path may comprise a licensed non-line of sight wirelesscommunication link). Another such backhaul link path may provideunpredictable reliability (e.g., subject to unpredictable interference)but provide relatively high capacity (e.g., the unpredictablereliability backhaul link may comprise an unlicensed non-line of sightwireless communication link). Operation of such a heterogeneous backhaullink configuration according to embodiments of the invention supportsadditional backhaul capacity beyond that which can be transported by thehigh reliability path alone. Thus, although the risk of overflow fromthe high reliability path may be high due to the limited availability ofhigh reliability link capacity, both high reliability and unpredictablereliability paths can be used simultaneously to provide backhaultransport meeting QoS policies for the backhaul link, thereby avoidingor minimizing dropping of data during periods of congestion. Forexample, in particular circumstances the unpredictable reliability pathof a backhaul link may be used to carry backhaul traffic (e.g., lowpriority traffic, best efforts traffic, etc.) during periods in which ahigh reliability path of the backhaul link experiences congestion.

The foregoing has outlined rather broadly the features and technicaladvantages of the present invention in order that the detaileddescription of the invention that follows may be better understood.Additional features and advantages of the invention will be describedhereinafter which form the subject of the claims of the invention. Itshould be appreciated by those skilled in the art that the conceptionand specific embodiment disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present invention. It should also be realized by thoseskilled in the art that such equivalent constructions do not depart fromthe spirit and scope of the invention as set forth in the appendedclaims. The novel features which are believed to be characteristic ofthe invention, both as to its organization and method of operation,together with further objects and advantages will be better understoodfrom the following description when considered in connection with theaccompanying figures. It is to be expressly understood, however, thateach of the figures is provided for the purpose of illustration anddescription only and is not intended as a definition of the limits ofthe present invention.

BRIEF DESCRIPTION OF THE DRAWING

For a more complete understanding of the present invention, reference isnow made to the following descriptions taken in conjunction with theaccompanying drawing, in which:

FIGS. 1A-1D show systems adapted to use heterogeneous backhaul linkconfigurations implementing backhaul link path selection control toprovide traffic offloading for traffic congestion mitigation accordingto embodiments of the invention;

FIG. 2 shows detail with respect to heterogeneous backhaul link nodeconfigurations according to embodiments of the invention;

FIG. 3 shows a flow diagram of backhaul link path selection control withrespect to a point-to-point backhaul transport configuration ofembodiments of the invention; and

FIG. 4 shows a flow diagram of backhaul link path selection control withrespect to a point-to-multipoint backhaul transport configuration ofembodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1A shows system 100 using heterogeneous backhaul linkconfigurations implementing backhaul link path selection control toprovide traffic offloading for traffic congestion mitigation accordingto embodiments of the invention. In particular, system 100 includesexemplary point-to-point backhaul transport portion 110 andpoint-to-multipoint backhaul transport portion 120 providingcommunication between various devices (e.g., user devices 101 a-101 g)and other nodes (e.g., nodes of network 150), as will be discussed infurther detail below.

User devices 101 a-101 g may comprise any number of forms of devices forwhich data communication is utilized, such as smart phones (e.g., userdevices 101 a, 101 d, and 101 g), personal digital assistants (PDAs)(e.g., user device 101 b), personal computers (PCs) (e.g., user devices101 c and 101 f), cellular telephones (e.g., user device 101 e),personal media players, Internet appliances, etc. Communication may beprovided by the links of system 100 by and between such user devicesand/or other devices (e.g., hubs 111 and 121, access points 113 and 123a-123 c, and nodes of network 150).

Network 150 may comprise various forms of networks, such as local areanetworks (LANs), metropolitan area networks (MANs), wide area networks(WANs), the Internet, the public switched telephone network (PSTN),cellular networks, cable transmission networks, etc. Accordingly, dataoriginated from and/or directed to various devices (e.g., user devices101 a-101 g, hubs 111 and 121, and access points 113 and 123 a-123 c)may be carried by network 150.

Access points 113 and 123 a-123 c providing communication links withrespect to the user devices may comprise various forms of communicationsnodes. For example, access points 113 and 123 a-123 c may comprise WiFiaccess points, 3G and/or 4G access points, femto cells, base stations,radio base repeaters, and/or the like. Similarly, hubs 111 and 121providing communication links with respect to access points 113 and 123a-123 c may comprise various forms of communications nodes. For example,hubs 111 and 121 may provide hub configurations which include switch,router, gateway, and/or the like functionality operable to facilitatecommunications as described herein.

Although shown in the embodiment illustrated in FIG. 1A as singledevices, it should be appreciated that access points and/or hubs hereinmay be provided as a plurality of separate devices. For example, anembodiment may utilize a hub device coupled to a backhaul link device(e.g., hub 111 a coupled to backhaul interface 111 b forming hub 111 ofFIG. 1B). Likewise, an embodiment may utilize an access point devicecoupled to a backhaul link device (e.g., access point 113 a coupled tobackhaul interface 113 b forming access point 113 of FIG. 1B).

To facilitate the communication of data by and between the variousdevices, backhaul links 112 and 122 a-122 c are implemented betweenrespective ones of hubs 111 and 121 and access points 113 and 123 a-123c. That is, in the illustrated embodiment, backhaul link 112 providespoint-to-point backhaul communication between hub 111 and access point113, such as for communication of data originated from and/or directedto user devices 101 a-101 c and/or access point 113. Similarly, backhaullinks 122 a-122 c provide point-to-multipoint backhaul communicationbetween hub 121 and access points 123 a-123 c, such as for communicationof data originated from and/or directed to user devices 101 d-101 gand/or access points 123 a-123 c.

Although the links between the access points and user devices andbetween the access points and hubs of the illustrated embodiment areshown as wireless links (e.g., RF links, such as cellular communicationlinks, WiFi links, WiMax links, wireless LAN (WLAN) links, BLUETOOTHlinks, etc.), it should be appreciated that there is no limitation tothe use of wireless links according to embodiments herein. For example,one or more of the links between an access point and an associated userdevice and/or between a hub and an associated access point may comprisea wireline link (e.g., copper cable or fiber optic links). Likewise,although the links between the hubs and remainder of the network of theillustrated embodiment are shown as wireline links, there is nolimitation to the use of wireline links according to embodiments herein.Accordingly, one or more of these links may comprise a wireless linkaccording to embodiments herein.

It should be appreciated that both point-to-point backhaul linktransport portion 110 and point-to-multipoint backhaul transport portion120 of the illustrated embodiment include heterogeneous backhaul linksadapted for traffic offloading for traffic congestion mitigation. Inparticular, backhaul link 112 of point-to-point backhaul link transportportion 110 of embodiments provides a heterogeneous backhaul linkconfiguration implementing a plurality of data paths, wherein the datapaths provide different capabilities (e.g., differing reliability,robustness, etc.). Similarly, backhaul link 122 b of point-to-multipointbackhaul link transport portion 120 of embodiments provides aheterogeneous backhaul link configuration implementing a plurality ofdata paths, wherein data paths provide different capabilities. Forexample, backhaul links 112 and 122 b of embodiments herein may comprisea high reliability path (e.g., using licensed RF spectrum) and anunpredictable reliability path (e.g., using unlicensed RF spectrum).

The high reliability paths and unpredictable reliability paths utilizedaccording to embodiments may comprise various configurations ofcommunication paths and may be designated as high reliability orunpredictable reliability depending upon attributes relevant to theparticular situation. For example, high reliability paths andunpredictable reliability paths can be predetermined (e.g. licensednon-line of sight (NLOS) paths may be designated as high reliabilitypaths while unlicensed WiFi paths may be designated as unpredictablereliability paths). Additionally or alternatively, high reliabilitypaths and unpredictable reliability paths can be determined by themonitoring the communication links (e.g., packet error rate (PER),receive signal strength indication (RSSI), signal to interference plusnoise ratio (SINR), etc.), wherein the designation as high reliabilityand unpredictable reliability may be dynamically changed in response tosuch monitoring. It should be appreciated from the foregoing that themultiple paths of a heterogeneous backhaul link need not comprisecommunication paths of a same network, and thus traffic may be offloadedto different networks according to embodiments herein.

Although the data paths of the illustrated embodiment are both shown aswireless links, it should be appreciated that there is no limitation tothe use of such wireless links according to embodiments herein. Forexample, one or more of the data paths of a heterogeneous backhaul linkmay comprise a wireline link, such as wireline link 112 a of FIG. 1C. Ascan be appreciated from the embodiment illustrated in FIG. 1C, a mixtureof wirleline links (e.g., wireline link 112 a) and wireless links (e.g.,wireless link 112 b) may be utilized in providing a heterogeneousbackhaul link. Moreover, there is no limitation to the use of two pathsin a heterogeneous backhaul link, as shown in FIG. 1D.

The high reliability path provides a primary backhaul link data pathaccording to embodiments, and thus all data flows over the highreliability path when there is no congestion on the high reliabilitypath. However, when there is congestion on the high reliability path,path selection logic of embodiments herein selects which data flows arerouted through the unpredictable reliability path. For example, lowpriority data flows (e.g., data flows having low QoS requirements,source or destinations identified as low priority, associated withapplications designated as low priority, etc.) may be routed over theunpredictable reliability path during periods of high reliability pathcongestion. Stated another way, in case of high reliability pathcongestion, excess lowest priority data flows are preferably routed overthe unpredictable reliability path and all other traffic is preferablyrouted over the high reliability path. In operation according toembodiments, only the low priority flows needed to provide capacityrelief with respect to the high reliability path are routed over theunpredictable reliability path. The low priority flows are preferablyagain routed over the high reliability path when the high reliabilitypath congestion has receded. For example, after a period (e.g., secondsor minutes) of high reliability path capacity availability (e.g., athreshold percentage of free capacity, a threshold amount of freecapacity, free capacity sufficient to accommodate one or more flowscurrently routed over the unpredictable reliability path, etc.), one ormore low priority flow may be rerouted over the high reliability path.

As can be appreciated from the foregoing, a goal according toembodiments is to keep the high reliability path operating at or nearcapacity. Thus, the unpredictable reliability path is used according toembodiments only for low priority data flows as a “best efforts” attemptto provide transport without dropping the flows. In operation accordingto embodiments, the path selection logic implements prioritization withrespect to the flows routed over the unpredictable reliability path toaddress congestion experienced with respect to this link (e.g.,determining which flows are to be dropped when both the high reliabilitypath and unpredictable reliability path are congested).

Directing attention to FIG. 2, a block diagram showing detail withrespect to hub 210 and access point 220 providing heterogeneous backhaullink 201 according to embodiments is shown. It should be appreciatedthat hub 210 of FIG. 2 may correspond to any of a number of hubsproviding backhaul communication, such as either of hubs 111 and 121 ofFIG. 1A. Similarly, access point 220 of FIG. 2 may correspond to any ofa number of access points providing backhaul communication, such aseither of access points 113 and 123 b of FIG. 1A.

The detail provided in FIG. 2 comprises functional blocks utilized inproviding backhaul communications using a heterogeneous backhaul linkconfiguration according to embodiments herein. Accordingly, additionalfunctional blocks that may form a part of a hub and/or access point, butwhich are not specifically adapted to the use of a heterogeneousbackhaul link may not be shown. For example, appropriate networkinterface functional blocks may be coupled to interfaces 219 of hub 210to facilitate connection to network 150. Similarly, appropriate radiofunctional blocks may be coupled to interfaces 229 of access point 220to facilitate connection to user devices of user devices 101 a-101 g.Such additional functionality is well known to those of ordinary skillin the art and thus will not be described in detail herein.

Although discussed with reference to circuitry of a hub and accesspoint, it should be appreciated that the circuitry of FIG. 2 may beprovided separate from a corresponding hub, access point, or otherdevice with which backhaul communications are facilitated using theheterogeneous backhaul link configurations herein. For example, thecircuitry of hub 210 and/or access point 220 may comprise an applique orexternal device which may be coupled to another device (e.g., networknode, such as a network hub or access point facilitating networkcommunications) to provide backhaul communications as described herein.

The embodiment illustrated in FIG. 2 provides a backhaul link in whichboth ends (hub 210 and access point 220) have a plurality of radios(high reliability path radio 213 and unpredictable reliability pathradio 216 for hub 210 and high reliability path radio 223 andunpredictable reliability path radio 226 for access point 220) which areoperable simultaneously to provide the plurality of data paths of theheterogeneous backhaul link. The radios may comprise circuitry (e.g.,transceiver radios 215, 218, 225, and 228, filters 214, 217, 224, and227, modulators, analog to digital converters, digital to analogconverters, digital signal processors, mixers, etc.) appropriate toproviding the communications for the corresponding data path. The radiosof either end of the heterogeneous backhaul link are preferably adaptedto provide data paths having different capabilities (e.g., differingreliability, robustness, etc.), such as may comprise the use ofdifferent RF spectrum, different communication protocols, differentmodulation schemes, different data rates, etc. For example, highreliability path radios 213 and 223 may be adapted to utilize licensedRF spectrum and associated communications protocols for providing a highreliability path of the backhaul link while unpredictable reliabilitypath radios 216 and 226 may be adapted to utilize unlicensed RF spectrumand associated communications protocols for providing an unpredictablereliability path of the backhaul link.

It should be appreciated that, although two radios are shown for eachend in the illustrated embodiment, different numbers of radios may beutilized by embodiments of the invention (e.g., providing a plurality ofhigh reliability paths and/or a plurality of unpredictable reliabilitypaths). Moreover, the particular configuration of the plurality ofradios may differ than that shown in the illustrated embodiment. Forexample, rather than comprising separate radios as in the illustratedembodiment, multiple radios as used according to embodiments herein maybe mechanically packaged together.

In operation according to embodiments of the invention, backhaul linkpath selection control is implemented with respect to one or more nodeof a backhaul link (e.g., hub 210 and/or access point 220 providingbackhaul link 201) for optimizing backhaul transport using theaforementioned heterogeneous backhaul link configurations by providingtraffic offloading for traffic congestion mitigation. For example,backhaul link path selection control of embodiments implements logic fordetermining when data is to be carried via one or more of the backhaullink paths of a heterogeneous backhaul link. Accordingly, hub 210 andaccess point 220 of the embodiment illustrated in FIG. 2 include digitalfront end circuitry 211 and 221, respectively. Digital front endcircuitry of embodiments comprises a processor-based system operableunder control of an instruction set to provide operation as describedherein. Such processor-based systems may comprise a general purposeprocessor (e.g., a central processing unit (CPU), such as a processorfrom the CORE line of processors available from Intel Corporation)and/or a special purpose processor (e.g., an application specificintegrated circuit (ASIC) (e.g., with an ARM processor) or a fieldprogrammable gate array (FPGA)), associated circuitry (e.g., memory,input/output, interfaces, etc.), and instruction set (e.g., software,firmware, logic algorithms, etc.).

Digital front end circuitry 211 and 221 of the illustrated embodimentcomprise path selection logic 212 and 222, respectively, operable toprovide backhaul link path selection responsive to current backhaultraffic conditions. Such logic implements a single QoS or other dataflow priority (e.g., source or destinations priority, applicationspriority, etc.) function with respect to the multiple paths of thebackhaul link according to embodiments herein. For example, backhaullink path selection control provided by the path selection logic maydetermine, during periods of backhaul congestion, that some portion ofthe backhaul data is to be carried by the high reliability path (e.g.,using high reliability path radios 213 and 223), another portion of thebackhaul data is to be carried by an unpredictable reliability path(e.g., using unpredictable reliability path radios 216 and 226), and/orstill another portion of the data is to be dropped (e.g., by digitalfront end circuits 211 and 221) based upon QoS and/or other attributesof the data flows. Accordingly, both high reliability and unpredictablereliability paths can be used simultaneously to provide backhaultransport, thereby avoiding or minimizing dropping of data duringperiods of backhaul link congestion. For example, in particularcircumstances the unpredictable reliability path of backhaul link 201may be used to carry backhaul traffic (e.g., low priority traffic, bestefforts traffic, etc.) during periods in which the high reliability pathof backhaul link 201 experiences congestion.

It should be appreciated that, although the path selection logic 212 and222 is shown in the illustrated embodiments as being separate from theradios, and being operable to receive signaling from the radios (e.g.,PER, etc.) and to make routing decisions for the data flows, embodimentsof the invention are not limited to such configurations. For example,embodiments of the invention may utilize a configuration in which pathselection logic is integrated with the high reliability radio andoperable, in a heterogeneous backhaul link implementation, to receivesignaling from the unpredictable reliability radio.

In operation according to embodiments of the invention, path selectionlogic 212 and/or 222 operates to allocate data flows to the highreliability path or unpredictable reliability path of a backhaul linkbased upon various information in or associated with the data flows. Forexample, service classes and QoS attributes are provisioned such thatnetwork traffic may be classified into a particular service class basedon packet parameters such as propagate bit (p-bit) or type of service(TOS) bits. Traffic allocation to the backhaul link paths, as well asdeterminations regarding flows to be dropped, may implement decisionsbased upon traffic priority (e.g., using QoS markings in the datapackets) and information regarding the congestion of the highreliability path (e.g., level of congestion, source of congestion,etc.). For example, path selection logic of embodiments may determinethe paths to carry particular data flows based on congestion and QoSrequirements for the particular data flows. The path selection logic ofembodiments preferably does not change the packet data, such as p-bitsor TOS bits, but rather makes backhaul link path data routing and/ordata dropping decisions using the data.

It should be appreciated that, although an exemplary embodiment has beendescribed above with reference to the use of QoS attributes for backhaullink path data flow routing decisions and/or data flow droppingdecisions, embodiments of the invention may utilize additional oralternative information. For example, embodiments operate to analyze thepayload data to determine one or more aspect of the data flows (e.g.,the type of application associated with the data flow, the source and/ordestination of the data flow, the type of data carried in the data flow,etc.) in determining the backhaul link path routing for particular dataflows during periods in which a high reliability path is congested. Pathselection logic may operate to route data flows for particularapplications (e.g., “low priority” applications, such as Internetbrowser traffic, media streaming traffic, etc.) through an unpredictablereliability link during periods of high reliability link congestion.Additional or alternative information used in decision making by pathselection logic of embodiments includes a source of the congestion, thequality of the unpredictable reliability path, fairness metrics for thedata flows, and/or the like.

Although operation of path selection logic of exemplary embodiments hasbeen described above with respect to priority based path selection forthe various data flows, it should be appreciated that path selectionlogic of embodiments further operates to provide priority basedselection for data flows carried by a particular path. For example, pathselection logic herein may operate to prioritize the data flowsinitially selected for routing through the unpredictable reliabilitypath during periods of high reliability path congestion. In particular,the traffic offloaded from the high reliability path may itself besufficient to cause congestion on the unpredictable reliability path.Thus, path selection logic of embodiments herein may further prioritizethese data flows (e.g., based upon QoS requirements for the data flows,fairness metrics for the data flows, aspects of the data flows, and/orthe like). The lower priority ones of the data flows initially routed tothe unpredictable reliability path may be dropped, or routed to yet aless desirable path (e.g., more unpredictable reliability, poorerquality, etc.), to a point at which the unpredictable reliability pathcapacity is not exceeded.

The foregoing heterogeneous backhaul links implemented according toembodiments of the invention may facilitate communication with respectto a number of different backhaul transport configurations. For example,backhaul transport configurations of embodiments of the inventionprovide operation for optimizing point-to-point backhaul link transport(e.g., point-to-point backhaul transport portion 110 of FIG. 1A).Likewise, backhaul transport configurations according to embodimentsherein provide operation for optimizing point-to-multipoint backhaullink transport (e.g., point-to-multipoint backhaul transport portion 120of FIG. 1A).

In a point-to-point backhaul transport configuration the path selectionlogic may provide for all backhaul data to be carried by a highreliability path of the point-to-point backhaul link (e.g., the highreliability path of heterogeneous backhaul link 112 of FIG. 1A) untilthe capacity of that path is neared or reached. Thereafter, the pathselection logic may determine data to be carried by an unpredictablereliability path of the point-to-point backhaul link (e.g., theunpredictable reliability path of heterogeneous backhaul link 112)during the period in which the high reliability path is experiencingcongestion. Flow 300 of FIG. 3 shows operation of embodiments of pathselection logic (e.g., path selection logic 212 and/or path selectionlogic 222 of hub 210 and access point 220 of FIG. 2) to provide dataflow routing and/or dropping control with respect to a point-to-pointheterogeneous backhaul link configuration consistent with the foregoing.

At block 301 of the illustrated embodiment all data flows are routedover the high reliability path of the heterogeneous backhaul link.Accordingly, the high reliability path provides a primary backhaul linkdata path according to the illustrated embodiment.

At block 302 a determination is made as to whether the high reliabilitypath is experiencing congestion. For example, the demand for backhauldata flow communication may be analyzed with respect to the capacity ofthe high reliability path to determine if the high reliability path isat or near capacity. If the high reliability path is not congested,processing according to the illustrated embodiment returns to block 301for all data flows to be routed over the high reliability path. However,if the high reliability path is congested, processing according to theillustrated embodiment proceeds to block 303.

At block 303 of the illustrated embodiment the backhaul data flows areprioritized. For example, the data flows may be prioritized based uponQoS requirements for the data flows, fairness metrics for the dataflows, aspects of the data flows (e.g., application type, Internetprotocol (IP) address, port, etc.), and/or the like.

At block 304 the quality (e.g., reliability measure) of theunpredictable reliability path of the heterogeneous backhaul link isanalyzed (e.g. PER, RSSI, SINR, etc.). For example, because of theunpredictable reliability of the path, the quality of the path may varywith time, such as due to variations in interference, noise, etc. Theinstantaneous quality of the unpredictable reliability path may limitthe capacity, bandwidth, throughput, or even availability of theunpredictable reliability path at any particular time.

One or more lower priority data flows sufficient to alleviate thecongestion being experienced on the high reliability path (e.g., demandin excess of the high reliability path capacity) is offloaded from thehigh reliability path at block 305. For example, a number of the lowestpriority data flows, as determined by the data flow prioritization, maybe selected for offloading from the high reliability path to avoid thecongestion. It should be appreciated that the data flows offloaded,although described above as “lower priority” data flows, may includehigh priority data flows (e.g., lower priority ones of the high prioritydata flows). For example, where the analysis of the quality of theunpredictable reliability path indicates that the quality of the path ishigh, higher priority data flows may be offloaded where congestion ishigh and/or low priority data flows are few.

A determination is made as to whether the data flows offloaded from thehigh reliability path exceed the capacity of the unpredictablereliability path at block 306. For example, the present channelconditions experienced in the unpredictable reliability path mayestablish a particular level of capacity available with respect to theunpredictable reliability path which may or may not be sufficient tocarry any or all of the data flows offloaded from the high reliabilitypath.

If, at block 306, it is determined that the data flows offloaded fromthe high reliability path do not exceed the capacity of theunpredictable reliability path, processing according to the illustratedembodiment proceeds to block 307. At block 307 all of the data flowsoffloaded from the high reliability path are routed over theunpredictable reliability path.

If, however, at block 306, it is determined that the data flowsoffloaded from the high reliability path do exceed the capacity of theunpredictable reliability path, processing according to the illustratedembodiment proceeds to block 308. At block 308 a sufficient number ofthe data flows offloaded from the high reliability path are dropped toallow the remainder of the offloaded data flows to be routed over theunpredictable reliability path. For example, a number of the lowestpriority data flows offloaded from the high reliability path, asdetermined by the data flow prioritization, may be selected for droppingwhile the remaining data flows offloaded from the high reliability pathare routed over the unpredictable reliability path.

In operation according to embodiments of the invention, fairness logicmay be applied with respect to the determination to drop one or moredata flows. For example, where a plurality of data flows with the samepriority are present in the offloaded data flows and unpredictablereliability path capacity allows for carrying some, but not all, suchdata flows, embodiments may implement a fairness scheme to avoid unfairresults. In one embodiment, path selection logic may comprise memory todetermine a particular user device, origination point, destinationpoint, application type, etc. having had an associated data flowpreviously dropped and thus select a data flow for a different userdevice, origination point, destination point, application type, etc. tobe dropped. In another embodiment, path selection logic may employ arandomizer when selecting the particular data flow to be dropped,thereby implementing some level of fairness over time.

After routing all of the offloaded data flows over the unpredictablereliability path (block 307) or dropping some offloaded data flows(block 308), processing according to the illustrated embodiment proceedsto block 309. At block 309 a determination is made as to whether thetraffic demand has receded such that all the data flows may be carriedby the high reliability path. If the backhaul traffic demand has notreceded to a point that the high reliability path can carry all of thedata flows, processing according to the illustrated embodiment returnsto block 303 for operation to make routing decisions appropriate to anychanges in the congestion then being experienced. However, if thebackhaul traffic demand has receded to a point that the high reliabilitypath can carry all of the data flows, processing according to theillustrated embodiment returns to block 301 for routing of all the dataflows over the high reliability path.

Determinations as to whether the traffic demand has receded such thatall data flows may be carried by the high reliability path may implementa hysteresis period (e.g., seconds or minutes) to avoid repeatedrerouting of data flows as a result of brief drops in traffic demand.For example, the determinations made at block 309 of embodiments maydetermine if the high reliability path capacity availability meets athreshold percentage of free capacity, a threshold amount of freecapacity, free capacity sufficient to accommodate one or more flowscurrently routed over the unpredictable reliability path, etc. for somethreshold amount of time before rerouting one or more low priority flowfrom the unpredictable reliability path to the high reliability path.

It should be appreciated that the routing of data flows over one oranother of the backhaul link paths is not limited to routing toalleviate congestion according to embodiments herein. For example, incase of high reliability path failure, all traffic may be routed overunpredictable reliability path. When the unpredictable reliability pathis at capacity, the lowest priority traffic may be dropped (e.g., thebandwidth of the unpredictable reliability path may be shared amongcompeting flows as per provisioned QoS rules). In case of unpredictablereliability path failure, all traffic may be routed over the highreliability path. When the high reliability path is at capacity, thelowest priority traffic may be dropped (e.g., the bandwidth of the highreliability path may be shared among competing flows as per provisionedQoS rules).

In a point-to-multipoint backhaul transport configuration the pathselection logic may provide for all backhaul data to be carried by highreliability paths of the point-to-multipoint backhaul links (e.g.,backhaul links 122 a and 122 c and the high reliability path ofheterogeneous backhaul link 122 b of FIG. 1A) until the capacity of ashared backhaul link resource of the high reliability paths is neared orreached. Thereafter, the backhaul link path selection control maydetermine data, if any, to be carried by an unpredictable reliabilitypath of one or more backhaul link of the point-to-multipoint backhaullinks (e.g., the unpredictable reliability path of heterogeneousbackhaul link 122 b) during the period in which the shared backhaul linkresource is congested. Flow 400 of FIG. 4 shows operation of embodimentsof path selection logic (e.g., path selection logic 212 and/or pathselection logic 222 of hub 210 and access point(s) 220 of FIG. 2) toprovide data flow routing and/or dropping control with respect to apoint-to-multipoint heterogeneous backhaul link configuration consistentwith the foregoing.

It should be appreciated that in point-to-multipoint operation, multipleones of access point 220 may be in communication with hub 210 (e.g., asrepresented in point-to-multipoint backhaul transport portion 120 ofFIG. 1A). One or more such access points may comprise high reliabilitypath radio 223, unpredictable reliability path radio 226, and pathselection logic 222 supporting a heterogeneous backhaul link. Moreover,access points utilized in accordance with embodiments of the inventionmay comprise high reliability path radio 223 without unpredictablereliability path radio 226 and path selection logic 222 supporting abackhaul link having only a high reliability path. In operationaccording to embodiments herein, the high reliability paths of eachbackhaul link of the point-to-multipoint backhaul transportconfiguration share resources (e.g., utilize a same channel frequency)such that capacity used with respect to one access point of themultipoint group is not available for use by the other access points ofthe multipoint group.

Although exemplary point-to-multipoint network configurations aredescribed below with reference to a network configuration including bothaccess point(s) having a multiple path backhaul link and access point(s)having a single path backhaul link, the concepts of the presentinvention are not limited to applicability to network configurationsincluding access points of each such type. For example, the conceptsherein may be utilized to provide offloading of low priority traffic atan access point having a multiple path backhaul link where anotheraccess point itself having a multiple path backhaul link is associatedwith high priority traffic causing the congestion.

At block 401 of the illustrated embodiment all data flows are routedover the high reliability paths of the point-to-multipoint backhaullinks. Accordingly, the high reliability paths provide the primarybackhaul link data paths according to the illustrated embodiment.

At block 402 a determination is made as to whether the high reliabilitypaths are experiencing congestion. For example, the demand for backhauldata flow communication may be analyzed with respect to the capacity ofthe high reliability path to determine if the high reliability path isat or near capacity (e.g., the shared capacity is fully, or within athreshold amount of fully, utilized). It should be appreciated that, dueto the shared nature of the high reliability path backhaul linkresources according to embodiments, the congestion may be associatedwith traffic spread across a number of the multipoint backhaul links ormay be concentrated in only one or a few of the multipoint backhaullinks. Nevertheless, the use of the shared capacity in any of themultipoint backhaul links renders that capacity unavailable for use inthe other multipoint links according to embodiments. If the highreliability paths are not congested, processing according to theillustrated embodiment returns to block 401 for all data flows to berouted over the corresponding high reliability paths. However, if thehigh reliability paths are congested, processing according to theillustrated embodiment proceeds to block 403.

At block 403 of the illustrated embodiment the backhaul data flows areprioritized. For example, the data flows may be prioritized based uponQoS requirements for the data flows, fairness metrics for the dataflows, aspects of the data flows (e.g., application type, Internetprotocol (IP) address, port, etc.), and/or the like.

At block 404 of the illustrated embodiment the quality of theunpredictable reliability path(s) of the heterogeneous backhaul link(s)is analyzed (e.g. PER, RSSI, SINR, etc.). For example, because of theunpredictable reliability of these paths, the quality of the path mayvary with time, such as due to variations in interference, noise, etc.The instantaneous quality of the unpredictable reliability path maylimit the capacity, bandwidth, throughput, or even availability of theunpredictable reliability path at any particular time.

As previously mentioned, the high reliability link congestion may beassociated with traffic spread across a number of the multipointbackhaul links or may be concentrated in only one or a few of themultipoint backhaul links. Accordingly, at block 405 a determination ismade as to the access point of the multipoint group associated with thetraffic causing the congestion. For example, the backhaul trafficassociated with (e.g., transmitted to and/or from) each access point ofthe multipoint group may be analyzed to determine the one or more accesspoints associated with the traffic causing the congestion. Where aparticular access point is associated with a predominant amount of thetraffic, that access point may be identified as associated with thecongestion. Where the traffic is spread across a number of accesspoints, the access points contributing some threshold level of traffic,or some percentage of traffic above other of the access points, may beidentified as associated with the congestion. Additionally oralternatively, the portion of the shared resources of the highreliability link used by communications associated with each accesspoint may be used in determining the source of congestion. For example,if communications associated with an access point are utilizing morethan some threshold of shared resources of the high reliability link, orif multiple access points are using more of the shared resources thanthe other access points, they may be identified as being associated withthe congestion.

As can be appreciated from the illustrated embodiment of flow 400, thepath selection logic may provide different routing of flows during highreliability path congestion depending upon the backhaul linkcapabilities of the access point associated with the congestion. Inoperation according to the illustrated embodiment, if the source of thecongestion is identified as an access point having a single pathbackhaul link (e.g., a high reliability link) processing proceeds toblock 406, if the source of the congestion is identified as an accesspoint having a backhaul link with multiple paths (heterogeneous backhaullink) processing proceeds to block 409, and if the source of thecongestion is identified as both an access point having a single pathbackhaul link and an access point having a backhaul link with multiplepaths processing proceeds to block 407.

It should be appreciated that although examples herein are discussedwith respect to an access point having a single path backhaul link andan access point having a multiple path backhaul link, the concepts arenot restricted to the use of a point-to-multipoint backhaul transportconfiguration having only two access points in communication with a hub.Accordingly, the concepts can be extended for multiple access points(e.g., a plurality of single path backhaul link access points and/or aplurality of multiple path backhaul link access points) and the analysisand determinations described below may be applied with respect to eachsuch access point.

When an access point having a single path backhaul link (e.g., a highreliability link) is identified as associated with the congestion, adetermination is made regarding the quality of the unpredictablereliability path(s) of the multipoint access points having multiplebackhaul link paths (e.g., a high reliability link and a unpredictablereliability link) and regarding the priority of the congestion traffic(i.e., the traffic associated with the access point identified with thecongestion) at block 406. The path selection logic of the illustratedembodiment provides different routing of flows during high reliabilitypath congestion depending upon the quality of the unpredictablereliability paths and the congestion traffic priority.

For example, when an access point having a single path backhaul link isidentified as associated with the congestion (block 405), if the qualityof the unpredictable reliability path(s) of the multipoint access pointshaving multiple backhaul link paths is poor and the priority of thecongestion traffic is low, processing according to the illustratedembodiment proceeds from bock 406 to block 408. At block 408 sufficientlow priority data flows associated with the single path backhaul linkcausing the congestion is dropped, thereby alleviating the congestion onthe high reliability paths. It should be appreciated that, in this case,the illustrated embodiment operates to drop low priority trafficassociated with an access point having a single path backhaul link toavoid “punishing” the traffic associated with an access point havingboth a high reliability path and an unpredictable priority path which isnot the source of the congestion. That is, low priority trafficassociated with the access point identified with the congestion isdropped rather than having traffic communicated by a different accesspoint offloaded to the unpredictable reliability path of its backhaullink to accommodate the congestion.

Processing according to the illustrated embodiment proceeds from block408 to block 411 for a determination as to whether the high reliabilitypaths remain congested after the low priority congestion traffic isdropped. If, after dropping the low priority congestion traffic, thehigh reliability paths are no longer congested, processing according tothe illustrated embodiment proceeds to block 412. However, if the highreliability paths remain congested (i.e., sufficient low prioritytraffic to alleviate the congestion is not dropped), processingaccording to the illustrated embodiment proceeds to block 409 whereinlow priority data flows (if any) associated with one or more multiplepath backhaul link not causing the congestion may be offloaded to acorresponding unpredictable reliability path to alleviate the congestionon the high reliability paths. In this case the illustrated embodimentoperates to offload low priority traffic associated with an access pointother than that associated with the traffic causing the congestion inorder to accommodate the high priority traffic at the access pointhaving a single path backhaul link. It should be appreciated that theextent of the “punishment” of the access points which are not associatedwith the cause of the congestion to accommodate high priority traffic ofanother access point is limited according to embodiments to low prioritytraffic (e.g., as may be associated with particular types of traffic,particular sources/destinations, particular applications, etc.).

Similarly, if an access point having a single path backhaul link isidentified as associated with the congestion (block 405), the quality ofthe unpredictable reliability path(s) of the multipoint access pointshaving multiple backhaul link paths is poor, and the priority of thecongestion traffic is high, processing according to the illustratedembodiment proceeds from block 406 to block 409. At block 409 lowpriority data flows (if any) associated with one or more multiple pathbackhaul link not causing the congestion may be offloaded to acorresponding unpredictable reliability path to alleviate the congestionon the high reliability paths. In this case the illustrated embodimentoperates to offload low priority traffic associated with an access pointother than that associated with the traffic causing the congestion inorder to accommodate the high priority traffic at the access pointhaving a single path backhaul link. It should be appreciated that theextent of the “punishment” of the access points which are not associatedwith the cause of the congestion to accommodate high priority traffic ofanother access point is limited according to embodiments to low prioritytraffic (e.g., as may be associated with particular types of traffic,particular sources/destinations, particular applications, etc.).Accordingly, in operation according to embodiments of the invention,high priority traffic is not offloaded to an unpredictable reliabilitypath to minimize the impact (e.g., QoS) to the communications which havenot been identified as a cause of the congestion. It should beappreciated that, where sufficient low priority traffic for offloadingto accommodate the high priority congestion traffic is not present withrespect to a multiple path backhaul link, high priority traffic which isidentified with the cause of the congestion may be dropped according toembodiments.

If an access point having a single path backhaul link is identified asassociated with the congestion (block 405), the quality of theunpredictable reliability path(s) of the multipoint access points havingmultiple backhaul link paths is good, and either the priority of thecongestion traffic is high or low, processing according to theillustrated embodiment proceeds from block 406 to block 409. Because thequality of the unpredictable reliability path is determined to be good,offloading of traffic from a high reliability path to a correspondingunpredictable reliability path, even for traffic not identified ascausing the congestion, is not expected to result in a significantimpact (e.g., QoS) to the offloaded traffic. Accordingly, the trafficcausing the congestion may thus be accommodated through offload oftraffic at a multiple path backhaul link without “punishing” of theaccess points which are not associated with the cause of the congestion.Of course, where the unpredictable reliability link does not providesufficient throughput to accommodate offloading of sufficient traffic toaccommodate the congestion traffic at the single path backhaul link,some of the congestion traffic may be dropped according to embodimentsherein.

When an access point having a multiple path backhaul link is identifiedas associated with the congestion, the path selection logic of theillustrated embodiment provides for offloading of traffic from the highreliability path to the corresponding unpredictable reliability path ofthe multiple path backhaul link. Accordingly, if an access point havinga multiple path backhaul link is identified as associated with thecongestion (block 405), processing according to the illustratedembodiment proceeds from block 405 to block 409. Because the traffic isassociated with an access point having a multiple path backhaul link,offloading of congestion traffic from a high reliability path to acorresponding unpredictable reliability path does not “punish” trafficwhich is not the cause of congestion. Accordingly, the traffic causingthe congestion may thus be accommodated through offload of at least someportion of the traffic at the multiple path backhaul link associatedwith the congestion. Of course, where the unpredictable reliability linkdoes not provide sufficient throughput to accommodate offloading ofsufficient traffic to accommodate the congestion traffic at the multiplepath backhaul link, some of the congestion traffic may be droppedaccording to embodiments herein.

When both an access point having a single path backhaul link and anaccess point having a multiple path back haul link are identified asassociated with the congestion, a determination is made regarding thequality of the unpredictable reliability path(s) of the multipointaccess points having multiple backhaul link paths and regarding thepriority of the congestion traffic (i.e., the traffic associated withthe access point identified with the congestion) at block 407. The pathselection logic of the illustrated embodiment provides different routingof flows during high reliability path congestion depending upon thequality of the unpredictable reliability paths and the congestiontraffic priority.

For example, if both an access point having a single path backhaul linkand an access point having a multiple path backhaul link are identifiedas associated with the congestion (block 405), the quality of theunpredictable reliability path(s) of the multipoint access points havingmultiple backhaul link paths is poor, and the priority of the congestiontraffic is low, processing according to the illustrated embodimentproceeds from block 405 to block 410. At block 410 low priority dataflows associated with the single path backhaul link causing thecongestion are dropped and low priority data flows associated with themultiple path backhaul link causing the congestion are offloaded to anunpredictable reliability path, thereby alleviating the congestion onthe high reliability paths. In operation according to embodiments, lowpriority traffic is offloaded to the unpredictable reliability pathsufficient to avoid or mitigate the contribution of congestion by thetraffic remaining on the high reliability path in association with themultiple path backhaul link. For example, with only 2 access pointssharing the backhaul link resource, each access point may use up to 50%of shared resources without causing congestion. If, however, the trafficassociated with one of the access points increases beyond 50% (e.g., to60%) of available capacity, that traffic may be identified as causingcongestion. In this case the excess 10% of this particular accesspoint's traffic may be offloaded to the unpredictable reliability path,assuming the access point has a multiple path backhaul link. Thisoffloading of traffic brings its traffic on the high reliability linkback to 50% of available capacity, and thus may no longer be consideredto cause congestion. It should be appreciated that, throughimplementation of the foregoing concepts, the illustrated embodimentoperates to optimize the offloading and dropping of low prioritycongestion traffic to minimize impact (e.g., QoS) at either access pointassociated with the congestion.

If, however, both an access point having a single path backhaul link andan access point having a multiple backhaul link are identified asassociated with the congestion (block 405), the quality of theunpredictable reliability path(s) of the multipoint access points havingmultiple backhaul link paths is poor, and the priority of the congestiontraffic is high, processing according to the illustrated embodimentproceeds from block 407 to block 409. At block 409 low priority dataflows (if any) associated with the multiple path backhaul link causingthe congestion may be offloaded to a corresponding unpredictablereliability path to alleviate the congestion on the high reliabilitypaths without impacting the high priority traffic at the single path andthe multiple path backhaul links, where possible. Moreover, as discussedabove, embodiments may operate to offload low priority trafficassociated with an access point other than that associated with thetraffic causing the congestion in order to accommodate the high prioritytraffic at other access points. It should be appreciated that the extentof the “punishment” of the access points which are not associated withthe cause of the congestion to accommodate high priority traffic ofanother access point is limited according to embodiments to low prioritytraffic (e.g., as may be associated with particular types of traffic,particular sources/destinations, particular applications, etc.).Accordingly, in operation according to embodiments of the invention,high priority traffic is not offloaded to an unpredictable reliabilitypath to minimize the impact (e.g., QoS) to the communications which havenot been identified as a cause of the congestion. It should beappreciated that, where sufficient low priority traffic for offloadingto accommodate the high priority congestion traffic is not present withrespect to a multiple path backhaul link, high priority traffic which isidentified with the cause of the congestion may be dropped according toembodiments.

If both an access point having a single path backhaul link and an accesspoint having a multiple path backhaul link are identified as associatedwith the congestion (block 405), the quality of the unpredictablereliability path(s) of the multipoint access points having multiplebackhaul link paths is good, and either the priority of the congestiontraffic is high or low, processing according to the illustratedembodiment proceeds from block 407 to block 409. Because the quality ofthe unpredictable reliability path is determined to be good, offloadingof traffic from a high reliability path to a corresponding unpredictablereliability path, even for traffic not identified as causing thecongestion, is not expected to result in a significant impact (e.g.,QoS) to the offloaded traffic. Accordingly, the traffic causing thecongestion may thus be accommodated through offload of traffic at amultiple path backhaul link (e.g., traffic of a multiple path backhaullink access point associated with the congestion) with little impact(e.g., QoS) on the traffic. Moreover, traffic may even be offloaded froman access point not associated with the congestion, if needed, without“punishing” such access points. Of course, where the unpredictablereliability link does not provide sufficient throughput to accommodateoffloading of sufficient traffic to accommodate the congestion trafficat the single path backhaul link, some of the congestion traffic may bedropped according to embodiments herein.

After offloading and/or dropping traffic at blocks 409 and 410, andafter it is determined that the high reliability paths are not congestedat block 411, processing according to the illustrated embodimentproceeds to block 412. At block 412 a determination is made as towhether the traffic demand has receded such that all the data flows maybe carried by the high reliability paths. If the backhaul traffic demandhas not receded to a point that the high reliability paths can carry allof the data flows, processing according to the illustrated embodimentreturns to block 403 for operation to make routing decisions appropriateto any changes in the congestion then being experienced. However, if thebackhaul traffic demand has receded to a point that the high reliabilitypath can carry all of the data flows, processing according to theillustrated embodiment returns to block 401 for routing of all the dataflows over the high reliability path.

As discussed above, determinations as to whether the traffic demand hasreceded such that all data flows may be carried by the high reliabilitypath may implement a hysteresis period (e.g., seconds or minutes) toavoid repeated rerouting of data flows as a result of brief drops intraffic demand. For example, the determinations made at block 412 ofembodiments may determine if the high reliability path capacityavailability meets a threshold percentage of free capacity, a thresholdamount of free capacity, free capacity sufficient to accommodate one ormore flows currently routed over the unpredictable reliability path,etc. for some threshold amount of time before rerouting one or more lowpriority flow from the unpredictable reliability path to the highreliability path.

It should be appreciated that the foregoing provides particular routingdecisions based upon the backhaul link configuration(s) associated withthe congestion, the quality of the unpredictable reliability link(s),and the priority of the congestion traffic as may be made by pathselection of embodiments herein are exemplary of application of theconcepts herein. Embodiments of the invention may operate to providedifferent routing determinations. Irrespective of the particular routingdeterminations made, embodiments operate to optimize the balance ofoffloading traffic to an unpredictable reliability link to accommodatecongestion traffic and impact to the data flows, while avoiding“punishing” flows which are not identified as the source of thecongestion. In operation according to embodiments, high reliabilityresources may be allocated evenly, or fairly, when there is congestion.Accordingly, low priority traffic may be dropped at the single pathbackhaul link access points if the low reliability links on the multiplepath backhaul link access points are unreliable and high prioritytraffic would be forced to the low reliability link.

As can be appreciated from the foregoing, in operation according toembodiments herein when there is overall congestion on the highreliability paths the system may disable or minimize the use of the highreliability paths for one or more access point having a multiple pathbackhaul link to alleviate congestion on the high reliability paths.Example decision criteria for implementing operation to reduce the highreliability path congestion include sending the lowest priority dataflows over one or more unpredictable reliability path for access pointsthat have a multiple path backhaul link. If high reliability pathcongestion remains after the offloading of data flows, embodiments mayfurther operate to also offload the next lowest priority data flows overone or more unpredictable reliability path, and so on (e.g., to thepoint that all data flows for one or more multiple path backhaul linkare offloaded to the unpredictable reliability paths, except perhapssignaling traffic). Accordingly, the excess traffic (i.e., congestiontraffic) and/or low priority data flows are routed via one or moreunpredictable reliability path during periods of congestion. Ascongestion reduces, traffic is brought back on to the high reliabilitypath, first with the high priority flows, then with the next highestpriority flows, etc., according to embodiments herein.

Also as can be appreciated from the foregoing, embodiments operate toimplement monitoring and adaptation of traffic routing determinationsbased upon the quality of the unpredictable reliability paths. A goal ofthis operation is to ensure fair allocation of traffic between the highreliability paths and unpredictable reliability paths. For instance, ifthere is too much low priority traffic on a backhaul link of an accesspoint having a single path (i.e., high reliability path) backhaul link,this traffic may overload the whole sector without application of theconcepts herein. Accordingly, backhaul link path selection control ofembodiments herein responds to this excess traffic by routing lowpriority data flows, and potentially even high priority data flows, ofmultiple path backhaul links over the unpredictable reliability paths.

By monitoring the reliability of the unpredictable reliability pathscarrying this rerouted traffic, embodiments can minimize the impact(e.g., QoS) on the rerouted data flows and avoid punishing high prioritytraffic associated with access points having a multiple path backhaullink due to excess low priority data flows associated with other accesspoints. For example, the quality of the unpredictable reliability pathsmay be monitored as well as the proportion of traffic that is lowpriority and high priority on each backhaul link and the overall trafficcongestion may be monitored. If the congestion is caused by excessivelow priority traffic on a single path backhaul link, then backhaul linkpath selection control of embodiments may reroute traffic of multiplepath backhaul links to an unpredictable reliability path, as long asthat unpredictable reliability path has good reliability. Otherwise, thebackhaul link path selection control may drop the excess low prioritytraffic of a single path backhaul link identified as causing thecongestion in order to relieve the congestion. If the congestion iscaused by excessive high priority traffic on a single path backhaullink, then backhaul link path selection control of embodiments mayreroute low priority traffic of multiple path backhaul links to anunpredictable reliability path. If the congestion is caused by excessivelow priority traffic on multiple path backhaul links, then backhaul linkpath selection control of embodiments may reroute low priority trafficof the multiple path backhaul links to the unpredictable reliabilitypaths.

Embodiments may utilize various weighting or other routing distributionalgorithms in implementing particular routing decisions herein. Forexample, a weighting algorithm may be applied with respect to the lowpriority traffic (e.g., based on the quality, such as PER, of anunpredictable reliability path) in determining whether to offload one ormore data flow associated with an access point having a multiple pathbackhaul link to the unpredictable reliability path. If theunpredictable reliability path or the low priority traffic implement anerror recovery mechanism (e.g., ARQ for link or TCP traffic), forexample, embodiments may operate to route a portion of the trafficassociated with an access point having a multiple path backhaul link toan unpredictable reliability path of that backhaul link in the foregoingsituations where determinations are made regarding the offloading ofdata flows to an unpredictable reliability link. Such embodiments mayoperate to monitor the latency (e.g., due to retransmission) of thesererouted data flows for providing control of the routing. For example,path selection logic may operate to gradually increase the amount ofrerouted traffic as long as the latency is acceptable.

In operation according to embodiments of the invention, determinationsregarding the routing of data flows are centralized. For example,although many access points may be active in the routing of particulardata flows over either an associated high reliability path orunpredictable reliability path, a single entity may operate to determinewhich flows are to be offloaded to the unpredictable reliabilitypath(s). Thus, although both hub 210 and access point 220 of FIG. 2 areshown as including path selection logic, only path selection logic 212of hub 210 may make the determinations set forth in flows 300 and 400 ofFIGS. 3 and 4 above. Path selection logic 222 of access point 220 maycontrol routing of particular data flows transmitted over the backhaullink, such as under control of path selection logic 212 of hub 210,without itself making the routing determinations. Accordingly, signaling(e.g., within a control channel, as part of packet header information,etc.) may be provided by hub 210 to access point 220 to control uplinkpath selection according to embodiments. Corresponding downlinksignaling may not be implemented, such as where access point 220 isoperable to monitor both high reliability path radio 223 andunpredictable reliability path radio 226 to thereby determine therouting determinations made by hub 210.

It should be appreciated from the foregoing that, in operation accordingto embodiments herein, the decisions regarding the routing of backhauldata made by the path selection logic of embodiments may be made withrespect to data flows rather than for individual data packets.Accordingly, the number of data flows, and correspondingly the number ofnetwork nodes, affected by the use of an unpredictable reliability pathfor backhaul transport of data and/or the dropping of data according toembodiments may be minimized. Moreover, there is no need for thereordering of the packets of each data flow, as the packets for a dataflow will be routed through one backhaul path (as opposed to the casewhere some packets of one data flow are routed ad hoc through multiplepaths, such as the high reliability path and unpredictable reliabilitypath, where the two paths could have different packet error rate and/orlatency, and hence the packets may arrive out of order at the receiver).

The routing decisions made by backhaul link path selection control ofembodiments are not restricted to applicability to offloading trafficfrom a high reliability path to a corresponding unpredictablereliability path of a backhaul link. For example, embodiments (e.g.,embodiments implementing a mesh network or other configuration havingappropriate communication paths available between various access pointsand/or other network nodes) may operate to reroute data flows from asingle path backhaul link to a multiple path backhaul link, such as fortransmission using an unpredictable reliability path of the multiplepath backhaul link, such as to avoid dropping one or more data flowduring periods of congestion

Although the present invention and its advantages have been described indetail, it should be understood that various changes, substitutions andalterations can be made herein without departing from the spirit andscope of the invention as defined by the appended claims. Moreover, thescope of the present application is not intended to be limited to theparticular embodiments of the process, machine, manufacture, compositionof matter, means, methods and steps described in the specification. Asone of ordinary skill in the art will readily appreciate from thedisclosure of the present invention, processes, machines, manufacture,compositions of matter, means, methods, or steps, presently existing orlater to be developed that perform substantially the same function orachieve substantially the same result as the corresponding embodimentsdescribed herein may be utilized according to the present invention.Accordingly, the appended claims are intended to include within theirscope such processes, machines, manufacture, compositions of matter,means, methods, or steps.

hat is claimed is:
 1. A method comprising: detecting congestion withrespect to communication over a high reliability path of a heterogeneousbackhaul link, wherein the heterogeneous backhaul link comprises thehigh reliability path and an unpredictable reliability path; andoffloading one or more data flow of the communication from the highreliability path to the unpredictable reliability path based at least inpart upon priority of the one or more data flow.
 2. The method of claim1, further comprising: monitoring communication over the highreliability path of the heterogeneous backhaul link after theoffloading; and rerouting at least a portion of the offloaded one ormore data flow from the unpredictable reliability path to the highreliability path when the monitoring indicates adequate capacity in thehigh reliability path for the at least a portion of the offloaded one ormore data flow.
 3. The method of claim 1, further comprising: analyzingquality of the unpredictable reliability path, wherein the offloadingthe one or more data flow of the communication from the high reliabilitypath to the unpredictable reliability path is also based at least inpart on the quality of the unpredictable reliability path.
 4. The methodof claim 3, wherein high priority data flows are offloaded from the highreliability path to the unpredictable reliability path when the qualityof the unpredictable reliability path is high.
 5. The method of claim 3,wherein only low priority data flows are offloaded from the highreliability path to the unpredictable reliability path when the qualityof the unpredictable reliability path is low.
 6. The method of claim 1,wherein the heterogeneous backhaul link is provided by a point-to-pointbackhaul transport configuration.
 7. The method of claim 1, wherein theheterogeneous backhaul link is provided by a point-to-multipointbackhaul transport configuration, the point-to-multipoint backhaultransport configuration including the heterogeneous backhaul linkproviding a multiple path backhaul link and at least one other backhaullink having a high reliability path sharing a resource with the highreliability path of the heterogeneous backhaul link.
 8. The method ofclaim 7, wherein the at least one other backhaul link comprises a singlepath backhaul link.
 9. The method of claim 7, wherein the at least oneother backhaul link comprise a multiple path backhaul link.
 10. Themethod of claim 7, further comprising: determining a backhaul linkassociated with the congestion; and controlling the offloading of theone or more data flow of the communication from the high reliabilitypath of the heterogeneous backhaul link to the unpredictable reliabilitypath also based at least in part on the backhaul link associated withthe congestion.
 11. The method of claim 10, wherein one or more lowpriority data flow carried by the at least one other backhaul link aredropped when the at least one other backhaul link is determined to beassociated with the congestion.
 12. The method of claim 10, furthercomprising: analyzing quality of the unpredictable reliability path,wherein one or more low priority data flow carried by the multiple pathbackhaul link is offloaded from the high reliability path to theunpredictable reliability path when the at least one other backhaul linkis determined to be associated with the congestion and the quality ofthe unpredictable reliability path is high.
 13. The method of claim 10,wherein one or more low priority data flow carried by the multiple pathbackhaul link is offloaded from the high reliability path to theunpredictable reliability path when the multiple path backhaul link isdetermined to be associated with the congestion.
 14. The method of claim13, further comprising: analyzing quality of the unpredictablereliability path, wherein one or more high priority data flow carried bythe multiple path backhaul link is offloaded from the high reliabilitypath to the unpredictable reliability path when the multiple pathbackhaul link is determined to be associated with the congestion and thequality of the unpredictable reliability path is high.
 15. The method ofclaim 1, wherein priority of the data flows is determined at least inpart from quality of service requirements for the data flows.
 16. Themethod of claim 1, wherein priority of the data flows is determined atleast in part from a source or destination of the data flows.
 17. Themethod of claim 1, wherein priority of the data flows is determined atleast in part from applications associated with the data flows.
 18. Asystem comprising: a first backhaul node having circuitry operable toestablish a heterogeneous backhaul link comprising a high reliabilitypath and an unpredictable reliability path; a second backhaul nodehaving circuitry operable to establish the heterogeneous backhaul link,wherein at least one of the first and second backhaul node includes pathselection logic operable to detect congestion on the high reliabilitypath and control offloading of one or more data flow from the highreliability path to the unpredictable reliability path during periods ofcongestion based at least in part on priority of the one or more dataflow.
 19. The system of claim 18, wherein the path selection logic isoperable to offload the one or more data flow from the high reliabilitypath to the unpredictable reliability path based at least in part on thequality of the unpredictable reliability path.
 20. The system of claim19, wherein the path selection logic is operable to offload highpriority data flows from the high reliability path to the unpredictablereliability path when the quality of the unpredictable reliability pathis high.
 21. The system of claim 19, wherein the path selection logic isoperable to only offload low priority data flows from the highreliability path to the unpredictable reliability path when the qualityof the unpredictable reliability path is low.
 22. The system of claim18, wherein the first and second backhaul node comprise nodes of apoint-to-point backhaul transport configuration.
 23. The system of claim18, wherein the first and second backhaul node comprises nodes of apoint-to-multipoint backhaul transport configuration, thepoint-to-multipoint backhaul transport configuration including theheterogeneous backhaul link providing a multiple path backhaul link andat least one other backhaul link having a high reliability path sharinga resource with the high reliability path of the heterogeneous backhaullink.
 24. The system of claim 23, wherein the path selection logic isoperable to control the offloading of the one or more data flow from thehigh reliability path to the unpredictable reliability path also basedat least in part on a backhaul link determined to be associated with thecongestion.
 25. The system of claim 24, wherein the path selection logicis operable to control one or more low priority data flow carried by theat least one other backhaul link being dropped when the at least oneother backhaul link is determined to be associated with the congestion.26. The system of claim 24, wherein the path selection logic is operableto control the offloading of the one or more data flow front the highreliability path to the unpredictable reliability path to cause one ormore low priority data flow carried by the multiple path backhaul linkto be offloaded from the high reliability path to the unpredictablereliability path when the at least one other backhaul link is determinedto be associated with the congestion and quality of the unpredictablereliability path is high.
 27. The system of claim 24, wherein the pathselection logic is operable to control the offloading of the one or moredata flow from the high reliability path to the unpredictablereliability path to cause one or more high priority data flow carried bythe multiple path backhaul link to be offloaded from the highreliability path to the unpredictable reliability path when the multiplepath backhaul link is determined to be associated with the congestionand the quality of the unpredictable reliability path is high.
 28. Amethod comprising: communicating data flows over at least one path of aheterogeneous backhaul link, wherein the heterogeneous backhaul linkcomprises a high reliability path and an unpredictable reliability path;detecting congestion with respect to communication over the highreliability path; analyzing quality of the unpredictable reliabilitypath; and offloading one or more data flow of the communication from thehigh reliability path to the unpredictable reliability path based atleast in part upon priority of the one or more data flow and the qualityof the unpredictable reliability path.
 29. The method of claim 28,further comprising: monitoring communication over the high reliabilitypath of the heterogeneous backhaul link after the offloading; andrerouting at least a portion of the offloaded one or more data flow fromthe unpredictable reliability path to the high reliability path when themonitoring indicates adequate capacity in the high reliability path forthe at least a portion of the offloaded one or more data flow.
 30. Themethod of claim 28, wherein the heterogeneous backhaul link is providedby a point-to-point backhaul transport configuration.
 31. The method ofclaim 30, wherein high priority data flows are offloaded from the highreliability path to the unpredictable reliability path when the qualityof the unpredictable reliability path is high.
 32. The method of claim30, wherein only low priority data flows are offloaded from the highreliability path to the unpredictable reliability path when the qualityof the unpredictable reliability path is low.
 33. The method of claim28, wherein the heterogeneous backhaul link is provided by apoint-to-multipoint backhaul transport configuration, thepoint-to-multipoint backhaul transport configuration including theheterogeneous backhaul link providing a multiple path backhaul link andat least one other backhaul link having a high reliability path sharinga resource with the high reliability path of the heterogeneous backhaullink.
 34. The method of claim 33, further comprising: determining abackhaul link associated with the congestion; and controlling theoffloading of the one or more data flow of the communication from thehigh reliability path to the unpredictable reliability path also basedat least in part on the backhaul link associated with the congestion.35. The method of claim 34, wherein one or more low priority data flowcarried by the at least one other backhaul link are dropped when the atleast one other backhaul link is determined to be associated with thecongestion.
 36. The method of claim 34, further comprising: analyzingquality of the unpredictable reliability path, wherein one or more lowpriority data flow carried by the multiple path backhaul link isoffloaded from the high reliability path to the unpredictablereliability path when the at least one other backhaul link is determinedto be associated with the congestion and the quality of theunpredictable reliability path is high.
 37. The method of claim 34,wherein one or more low priority data flow carried by the multiple pathbackhaul link is offloaded from the high reliability path to theunpredictable reliability path when the multiple path backhaul link isdetermined to be associated with the congestion.
 38. The method of claim37, further comprising: analyzing quality of the unpredictablereliability path, wherein one or more high priority data flow carried bythe multiple path backhaul link is offloaded from the high reliabilitypath to the unpredictable reliability path when the multiple pathbackhaul link is determined to be associated with the congestion and thequality of the unpredictable reliability path is high.
 39. The method ofclaim 28, wherein priority of the data flows is determined at least inpart from quality of service requirements for the data flows.
 40. Themethod of claim 28, wherein priority of the data flows is determined atleast in part from a source or destination of the data flows.
 41. Themethod of claim 28, wherein priority of the data flows is determined atleast in part from applications associated with the data flows.